Formation evaluation of Leonardian strata within the northern Spraberry Trend, West Texas

Abstract

The Spraberry Trend is defined by oil and gas production associated with Permian age fine-grained siliciclastic and carbonate strata located within the Midland Basin of West Texas. Since its discovery, production within the Spraberry Trend has been inconsistent, and few petrophysical studies of these low permeability reservoirs exit to examine the reasons for this inconstancy. A modern petrophysical study of the Spraberry Trend will aid in understanding these rocks and in determining the unconventional reservoir potential of this strata in the northwestern Midland Basin. The purpose of this research project is to complete a detailed petrophysical evaluation of Leonardian strata within Martin and Andrews counties of West Texas. Using public data from 50 wells and drill-core from two pilot wells, a petrophysical-workflow will document geologic heterogeneities throughout the study area. Petrophysical parameters of the Spraberry Trend will be determined through: 1) well-log data conditioning 2) deterministic and probabilistic well-log analysis 3) sedimentological core-descriptions 4) rock-to-log calibration 5) X-ray fluorescence analysis 6) stratigraphic analysis and 7) attribute mapping. This project will demonstrate the importance of combining geologic knowledge and petrophysical attributes to better understand these rocks and to fully characterize them as unconventional reservoirs. Results from this project will compliment previous work completed on the Spraberry Trend by implementing modern petrophysical techniques to characterize an otherwise under-studied region of the Midland Basin. Oil companies and future researchers will be able to integrate data from this project to better understand the regional geology the Permian Basin and other unconventional reservoir targets.